The present invention relates to apparatus for the decontamination of liquids and particularly to apparatus and methods for removal of hydrocarbons and other chemicals from liquids. While the present invention has particular application to the decontamination of storm water runoff from roads and parking lots, it will be understood that the invention also has application to other decontamination problems. For example, ponds, lakes, streams, and other bodies of water may be treated using the present invention and that the invention may even be used for decontaminating other liquids.
This invention is related to the prior invention of the applicant herein which is described in U.S. Pat. No. 4,555,201 entitled "Sediment Dike". This prior invention includes a tubular impervious exterior wall and a porous wall. Water with sediment and other contaminants are pumped into the envelope. The sediment and other particulate matter is captured and contained within the walls thereby forming a sediment dike. The water drains through the porous wall and is thus filtered before it drains from the dike.
The present invention utilizes much of the apparatus described therein and it will be understood that the present invention incorporates by reference the disclosure therein.
For a number of years there has been an increasing emphasis on ecology issues. Recent laws and regulations continue this emphasis to protect the public health and safety by requiring that storm water run-off and other contaminated water sources be cleaned of certain harmful oils, antifreeze, other hydrocarbons and chemicals before leaving a building site. Many major factories and processing plants have numerous types of contaminants in the form of dust or spills. These contaminants may come from the factory itself or from fleets of trucks and other vehicles on the premises that contribute to the contamination of these sites. The danger is that these contaminants are carried away with the rainwater to eventually leech into the soil, enter storm drains, contaminate rivers and bodies of water and eventually contaminate the underground water table that is a source of drinking water. Numerous other contamination clean up problems can benefit from this invention. Accordingly, there has been a demand, for at least several years, for apparatus that will assist in cleaning up waste ponds, large industrial parking lots and other contaminated bodies of water.
The prior art includes numerous methods and apparatus to clean dirty storm water and other chemical spills and contaminated bodies of water. These include settling ponds, sand filtration systems, containment units with skimmers, and chemical additives mixed with the dirty water that causes the contaminates to precipitate from the solution, and combination strainers and filters. Absorbent pillows and socks are used to soak up and absorb oil spills by surrounding the spill or just being placed in the oil spill and absorbing the oil. These absorbers tend to float, do not allow for through flow. Typically, they will only contain very small spills. For example, they typically will contain spills that are no more than a small percentage of their normal 3" height.
It is believed that all of the existing methods fail to clean the dirty water in a practical manner. Many of the chemical absorbent types quickly become blinded on the outermost surface due to all the sediment debris and contaminates that are exposed to the outer surface. The term blinded means that the outer surface or covering of the absorbent becomes plugged up with sediment, slime, debris, and other particles or solutions, thereby preventing further water flow through the absorber material. This blinding condition renders the balance of the absorbent, in that flow path, ineffective because it is not exposed to dirty water flow through the material. Therefore, the sock type absorber quickly loses utility.
The prior art apparatus and methods may do a good job with certain contaminants but fail to remove others. Most of these methods inherently have a high initial cost, a high operating cost, and are very complex to use. The net result is that there has not been a practical method of collecting and filtering out the rather minute levels of hydrocarbons and chemicals found in large bodies of water with sediment such as found in storm water run-off. This has led to the contamination of many sites remote from the site of the original contamination including the contamination of the underground water table.
It is an object of the present invention to provides for a very convenient and practical method of cleaning storm water run- off from parking lots, ponds or almost any contaminated body of water.